Maine Sen. Olympia Snowe is being castigated in her role as the sole Republican to vote in committee for overhauling America’s health care system. The vote has earned her the ire of Republicans and Democrats alike.

Conservatives have charged that she’s a traitor to small-government principles, while liberals have portrayed her as the “de facto president of the United States” who will derail efforts to enact a “public option” that would compete with private insurers. But Snowe’s reputation may wax with the passage of time, in the clearer light of historical hindsight.

Oftentimes, the consensus within either the Democratic or the Republican Party is a product of ideological blinders or groupthink — and the resulting policies are shortsighted and ultimately deeply flawed.

In recent decades, such voices of protest within a political party have occasionally proved to be far more insightful than anybody at the time cared to acknowledge or even contemplate.

For example, during the 1964 debate over the Gulf of Tonkin Resolution, Oregon Sen. Wayne Morse joined fellow Democratic Sen. Ernest Gruening of Alaska in casting the only “no” Senate votes against the resolution authorizing the use of force.

David Halberstam described Morse as a maverick “willing to go it alone on an issue of conscience.” Morse’s comments were particularly prescient about the impending disaster awaiting the United States in Southeast Asia.

He warned that approving the resolution was tantamount to granting war-making powers to the president without understanding the potential consequences of giving Lyndon B. Johnson a blank check to wage an open-ended ground war in Southeast Asia. If this resolution passes, “history will record that we have made a great mistake,” Morse predicted. He wasn’t wrong.

In 1985, a handful of rogue Democrats organized the Democratic Leadership Council. Under the leadership of then-Arkansas Gov. Bill Clinton and then-Sen. Al Gore of Tennessee, the DLC sought to move the Democratic Party toward more centrist, politically viable positions on issues ranging from crime and welfare to taxes and government spending. Their goal was to reach out to Reagan Democrats and expand their party’s appeal in presidential elections.

While the DLC angered more traditional liberals then ascendant, it’s clear, nearly a quarter-century later, that Clinton and Gore’s leadership made the party more competitive in presidential elections and erased the stigma of weakness from some of the party’s future standard-bearers. While the DLC’s policies weren’t uniformly successful and were filled with blind spots, Clinton and Gore won the White House in 1992 partly because of their heterodox efforts in the mid-to-late 1980s — a crucial, if little-recalled, moment in modern Democratic Party politics.

About the same time, President Ronald Reagan was infuriating his legions of conservative anti-Communist supporters by embracing arms control with Mikhail Gorbachev and negotiating with the “evil empire” of the Soviet Union.

Columnist George Will lambasted Reagan for being “wildly wrong” in his assessment of “what is happening in Moscow.” Reagan’s interest in arms control and deal making with the Russian bear was tantamount to presiding over “the moral disarmament of the West.” Will huffed that “actual disarmament will follow” because of Reagan’s failure of nerve.

With the benefit of hindsight, things didn’t turn out how Will and other prophets of doom envisioned them. Reagan’s decision to break with much of his party and with his own record of single-minded anti-communism, and seek accommodation with Gorbachev, was actually a bold diplomatic stroke.

In dissenting from his party’s mainstream, Reagan played at least a role in bringing a peaceful end to the Cold War and loosening the Soviet grip over Eastern Europe.

There is a lot to be said for elected officials who defy their party’s most vocal activists and vote their conscience on momentous issues. While these dissenters are not always standing on the right side of history, they have at least bucked the prevailing wisdom within their party and challenged the dominant voices within their ranks.

If President Barack Obama manages to enact reform that ultimately expands access to health care to millions of uninsured Americans, Snowe’s vote could come to be regarded as a Morse-, Clinton- and Reagan-like moment of intelligent defiance in the face of enormous pressure from within the Republican ranks. Future textbooks could well feature Snowe’s role in health care reform, much as Morse’s anti-war vote is recorded in books about the Vietnam debacle — and Snowe’s fiercest critics will most likely be cast into the dustbin of history.

Matthew Dallek is a visiting scholar at the Bipartisan Policy Center and acting director of the UC Davis Washington Program.